Management of Parathyroid Nodule
For an older adult presenting with a parathyroid nodule, particularly with suspected hyperparathyroidism, the primary approach is biochemical confirmation with serum calcium and parathyroid hormone (PTH) levels, followed by surgical excision (parathyroidectomy) as the definitive curative treatment for primary hyperparathyroidism (PHPT). 1, 2
Initial Diagnostic Workup
Biochemical Testing
- Measure serum calcium and intact PTH levels to confirm primary hyperparathyroidism, which is diagnosed when elevated or inappropriately normal PTH occurs with hypercalcemia 1, 2
- PHPT affects women more frequently (66 per 100,000 person-years) compared to men (25 per 100,000 person-years), with increasing prevalence 1, 2
High-Risk Population Screening
- Aggressive case finding is recommended for women older than 60 years and those with previous radiation treatment of the thyroid gland (radioactive iodine or therapeutic external beam radiation) 1
- Additional high-risk groups include those with previous thyroid surgery, type 1 diabetes mellitus, personal history of autoimmune disease, family history of thyroid disease, or atrial fibrillation 1
Imaging Evaluation
Preoperative Localization
- Ultrasound is the primary imaging modality for parathyroid adenoma localization 1
- Parathyroid adenomas account for 80-85% of PHPT cases, while multigland disease (multiple adenomas or hyperplasia) affects approximately 15-20% of patients 1, 2
Important Caveat: Thyroid Nodule Differentiation
- Parathyroid nodules can be mistaken for thyroid nodules on ultrasound, particularly when located behind the thyroid gland 3, 4
- If thyroid nodules are detected on preoperative ultrasound in patients with hyperparathyroidism living in iodine-deficient areas, thyroid scintigraphy should be performed even if TSH is normal to identify hot thyroid nodules that may require concurrent treatment 3
Genetic and Familial Considerations
Indications for Genetic Evaluation
- Refer to endocrinology and consider genetic counseling for patients with: 2
- Parathyroid adenoma diagnosed at age <30 years
- Multiple glands involved (multigland disease)
- Family history of hyperparathyroidism, pituitary adenoma, pancreatic islet cell tumor, or foregut carcinoid tumor (suggesting MEN1 or MEN2 syndromes)
Radiation History Impact
- Contrary to common belief, previous head and neck radiation exposure does not significantly increase the incidence of multigland disease (31% in radiation-exposed vs 28% in non-exposed patients, P=0.774) 5
- However, radiation-exposed patients tend to have smaller parathyroid glands (511 mg vs 790 mg, P=0.001) and lower preoperative PTH levels 5
Definitive Treatment
Surgical Management
- Parathyroidectomy is the curative treatment for PHPT, with two accepted operative strategies: 2
- Bilateral neck exploration (BNE)
- Minimally invasive parathyroidectomy (MIP)
- If hot thyroid nodules are identified, perform combined subtotal thyroidectomy and parathyroid resection in a single operation 3
Alternative for Non-Surgical Candidates
- Cinacalcet is indicated for hypercalcemia in patients with primary HPT for whom parathyroidectomy would be indicated based on serum calcium levels but who are unable to undergo surgery 6
- Starting dose: 30 mg twice daily, titrated every 2-4 weeks to normalize serum calcium 6
- Microwave ablation may be considered as an alternative minimally invasive option for patients unsuited or unwilling to undergo surgery, with significant reductions in nodule volume, PTH, and calcium levels at long-term follow-up 7
Post-Treatment Monitoring
Surveillance for Recurrence
- Monitor serum calcium and PTH levels postoperatively to confirm biochemical cure 2, 4
- Recurrence can occur from parathyromatosis (implantation of parathyroid tissue during initial surgery) or residual disease 8
- PTH levels may normalize temporarily after procedures (including fine needle aspiration causing hemorrhage) but can recur within months, requiring continued surveillance 4